<!DOCTYPE html>
<html>
    <head>
        <script src="vue.js"></script>
    </head>
    <body>
        <div id="app">
           <input type="text">
           
        </div>
        <script>
           Vue.directive('focus',{
               inserted(el,binding){
                   //if(binging.value){
                       el.focus();
                   //}
               }
           });

           var vm = new Vue({
               el:'#app'
           });
        </script>
    </body>
</html>